Religious belief impacts human health in a variety of ways, from blood pressure to psychological well-being.

Surveys regularly show that roughly 90 percent of Americans say they believe in God or some higher power and 50 percent say religion is very important to them.

Scientists have found a variety of possible ways in which faith affects our bodies and minds, from music and ritual to greater social connection, even the ability to forgive. And some recent research suggests that how people view God and their relationship with God can make a big difference in their psychological health.

Researchers at McLean Hospital near Boston found that those who believe in a benevolent God tend to worry less and be more tolerant of uncertainties than those who view God as indifferent or punishing. Their report, published in the Journal of Clinical Psychology in 2011, was based on surveys of Christians and Jews solicited through religious websites and organizations.

Researchers led by psychologist David Rosmarin said the findings are important because mental-health professionals need to consider religious attitudes in preparing treatment plans for individuals.

Scientists at Case Western University have found that many people who are deeply religious still experience anger toward God. Those feeling often coincide with deaths, illnesses, accidents or natural disasters, but can also surface in connection with personal disappointments or failures.

Their findings, published in early 2011 in the Journal of Personality and Social Psychology, indicate many people may see God as responsible for negative events, and feel abandoned or betrayed.

But people who are highly religious may have difficulty dealing with these feelings, since their faith instructs them to focus on the positive side of religious life.

Led by psychologist Julie Exline, the team surveyed college students, cancer survivors, grief-stricken family members and others over the past decade. They found that people identified as Protestant, African-Americans and/or older are less likely to report anger toward God, while some people who say they don't believe in God may still harbor anger.

But another study by sociologists at the University of Wisconsin-Madison found that people in violent relationships with intimate partners were able to find comfort through prayer.

The studies, based on interviews with dozens of victims from various backgrounds, showed that some used prayer to safely vent anger, while others used it to raise their sense of self worth, or to distract or reprieve them from the abuser.

Shane Sharp, the study's lead author and a graduate student at the time the research was done, said many victims also used prayer to forgive abusive partners, which could cause them to postpone leaving a relationship that should be abandoned.

Sharp said while religion is often pointed to as mostly positive or negative, the mechanics of prayer he encountered show it is often a mixed experience.